Many people have wondered why the Minnesota Twins -- owners of the third-worst starting pitching ERA in baseball -- would trade for a serviceable major league pitcher, Tommy Milone, only to stash him at Triple-A Rochester.

Couldn't Milone's career 3.84 ERA (4.13 FIP) help the Twins over the next couple months? Wouldn't it make more sense to let a 27-year-old like Milone build some equity in the rotation as opposed to 30-somethings like Kevin Correia and Yohan Pino?

Well, yes. And it'll happen soon. But it appears the Twins held Milone in Triple-A for a good reason.

Entering the season, Milone had racked up two years and 18 days of major league service time. One full year of service time is 172 days (there are 183 days in the 2014 major league season). If we do the math, Milone needed 154 days of service time this season (out of a possible 183) to reach three full years.

Because Milone was optioned to the minor leagues by the Oakland A's on July 5, all the Twins had to do was keep him at Triple-A through the first week of August to make sure he didn't reach three years of service time.

Why does this matter? Because players are eligible for arbitration after three years and free agency after six years. It's possible Milone could still reach arbitration this offseason as a "Super-2" candidate (which means a higher salary), but because the Twins held the soft-tossing lefty down for an extra week they now have him under team control for four seasons instead of three.

In what likely was his first and last start for Rochester on Tuesday night, Milone allowed one run on six hits over seven innings, striking out three while walking two.

Is this a "cheap" approach by the Twins? Actually no, because if all goes well with Milone over the next few years they'll wind up paying him for an extra year.

In what looks like a lost season, holding Milone back for a minute was probably a wise move.